/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.util.pattern;

import java.text.MessageFormat;

/**
 * Exception that is thrown when there is a problem with the pattern being parsed.
 *
 * @author Andy Clement
 * @since 5.0
 */
@SuppressWarnings("serial")
public class PatternParseException extends IllegalArgumentException {

    private final int position;

    private final char[] pattern;

    private final PatternMessage messageType;

    private final Object[] inserts;


    PatternParseException(int pos, char[] pattern, PatternMessage messageType, Object... inserts) {
        super(messageType.formatMessage(inserts));
        this.position = pos;
        this.pattern = pattern;
        this.messageType = messageType;
        this.inserts = inserts;
    }

    PatternParseException(Throwable cause, int pos, char[] pattern, PatternMessage messageType, Object... inserts) {
        super(messageType.formatMessage(inserts), cause);
        this.position = pos;
        this.pattern = pattern;
        this.messageType = messageType;
        this.inserts = inserts;
    }


    /**
     * Return a formatted message with inserts applied.
     */
    @Override
    public String getMessage() {
        return this.messageType.formatMessage(this.inserts);
    }

    /**
     * Return a detailed message that includes the original pattern text
     * with a pointer to the error position, as well as the error message.
     */
    public String toDetailedString() {
        StringBuilder buf = new StringBuilder();
        buf.append(this.pattern).append('\n');
        for (int i = 0; i < this.position; i++) {
            buf.append(' ');
        }
        buf.append("^\n");
        buf.append(getMessage());
        return buf.toString();
    }

    public int getPosition() {
        return this.position;
    }

    public PatternMessage getMessageType() {
        return this.messageType;
    }

    public Object[] getInserts() {
        return this.inserts;
    }


    /**
     * The messages that can be included in a {@link PatternParseException} when there is a parse failure.
     */
    public enum PatternMessage {

        MISSING_CLOSE_CAPTURE("Expected close capture character after variable name '}'"),
        MISSING_OPEN_CAPTURE("Missing preceeding open capture character before variable name'{'"),
        ILLEGAL_NESTED_CAPTURE("Not allowed to nest variable captures"),
        CANNOT_HAVE_ADJACENT_CAPTURES("Adjacent captures are not allowed"),
        ILLEGAL_CHARACTER_AT_START_OF_CAPTURE_DESCRIPTOR("Char ''{0}'' not allowed at start of captured variable name"),
        ILLEGAL_CHARACTER_IN_CAPTURE_DESCRIPTOR("Char ''{0}'' is not allowed in a captured variable name"),
        NO_MORE_DATA_EXPECTED_AFTER_CAPTURE_THE_REST("No more pattern data allowed after '{*...}' pattern element"),
        BADLY_FORMED_CAPTURE_THE_REST("Expected form when capturing the rest of the path is simply '{*...}'"),
        MISSING_REGEX_CONSTRAINT("Missing regex constraint on capture"),
        ILLEGAL_DOUBLE_CAPTURE("Not allowed to capture ''{0}'' twice in the same pattern"),
        REGEX_PATTERN_SYNTAX_EXCEPTION("Exception occurred in regex pattern compilation"),
        CAPTURE_ALL_IS_STANDALONE_CONSTRUCT("'{*...}' can only be preceeded by a path separator");

        private final String message;

        PatternMessage(String message) {
            this.message = message;
        }

        public String formatMessage(Object... inserts) {
            return MessageFormat.format(this.message, inserts);
        }
    }

}
